Despite that fact that extracorporeal shock wave lithotripsy (ESWL) has been in clinical use for over 15 years, the physical mechanisms of stone comminution and possible permanent damage to treated kidneys are still not well understood. In the original parent grant we showed that acoustic cavitation (the process of the growth and violent collapse of microscopic bubbles produced by the ESWL shock-wave field) is an important factor in both stone comminution and tissue damage. The goal of the renewed parent grant is to determine the precise role of cavitation in stone comminution and tissue damage so that we might optimize the safety and efficacy of lithotripsy treatment. This FIRCA grant enables us to broaden the scope of the parent grant by collaborating with the research group from the Acoustics Department of the Moscow State University (MSU) which is renowned for its theoretical expertise in classical and nonlinear acoustics, optics, laser physics, and computer modeling of complex physical processes. With the support of the original FIRCA grant an experimental setup has been built at MSU that makes possible precise measurements in the optoacoustics lithotripter at MSU. The goal of this proposal is to understand the fundamental aspects of shock wave interaction with cavitation bubbles. Specifically, we propose to utilize MSU expertise to develop an optical cavitation detection system, to design an efficient shock wave modeling algorithm, and to explore new ideas of cavitation control and manipulation. This renewal proposal requests funding for equipment to enable the MSU group to undertake a new series of experiments in shock wave propagation, cavitation visualization, and cavitation control. Joint experiments will be performed with the APL group, using tools previously developed in our collaborative work and utilizing the equipment purchased during original FIRCA funding. We request travel support to coordinate our respective efforts. This joint effort will promote lithotripsy research in both countries and enhance further collaboration.